Re: ENUM type
| From: | Alexey Borzov | Date: | Mon, 15 Jan 2001 16:06:27 +0000 |
| Subject: | Re: ENUM type | ||
| References: | 1 | Groups: | php.db |
| Request: | Send a blank email to php-db+get-5881@lists.php.net to get a copy of this message | ||
Greetings, Cahyo!
At 15.01.01, 18:47, you wrote:
CSA> I don't know what is the benefit if we use ENUM type.
CSA> can everybody explain it?
It is an ugly crutch.
Well, you see, most RDBMSes will allow you to make a 'lookup
table' or 'dictionary' or something (dunno its official name).
Something like:
CREATE TABLE foo_baz_dictionary (
baz integer not null primary key,
baz_name char(50)
);
-- baz is a potential "enum" field
CREATE TABLE foo (
bar integer,
...
baz integer,
foreign key (baz) references foo_baz_dictionary
);
Then when you insert something into 'foo', its 'baz' field is checked
against foo_baz_dictionary (which is far more manageable
than ENUM field definition).
MySQL does not support foreign keys and so its creators came up with ENUM
solution.
--
Yours, Alexey V. Borzov, Webmaster of RDW